1. Field of the Invention
The present utility model relates to a magnetic tape apparatus into and from which a tape cassette can be smoothly injected and ejected.
2. Related Arts
Conventional magnetic tape apparatus technologies include one described in the Unexamined Japanese Patent Application Publication No. Sho62-121953. An example thereof will be described with reference to FIG. 11 through FIG. 13. In this example, a pair of right and left guide plates 3a and 3b are disposed in a standing condition so as to be parallel to each other on a chassis 2 in a housing 1, and a plurality of guide rods 5 provided on both side surfaces of a tape cassette moving table 4 disposed between the guide plates 3a and 3b are movably inserted in a plurality of substantially L-shaped guide holes 6 formed through the guide plates 3a and 3b, so that the moving table 4 is formed so as to be movable in forward and backward directions a and b between a cassette injection position A and a cassette placement position B. Swinging levers 8 pivotally attached to the guide plates 3a and 3b through pivotal attachment shafts 7 so as to be rotatable in forward and backward directions c and d are engaged with the front guide rods 5. A worm gear 11 rotated by a drive source (not shown) is engaged with a worm gear 10 formed on a central part of the periphery of a rotating cam 9 disposed on the reverse surface of the chassis 2 so as to be rotatable. A bevel gear 12 formed on an upper part of the periphery of the rotating cam 9 and a gear 13 formed at the base end of the swinging lever 8 are coupled by a gear mechanism 14 with a clutch so as to interlock with each other. Reference numeral 15 represents a top plate disposed so as to hang between the guide plates 3a and 3b. 
As shown in FIG. 13, a concave groove 8a formed at the top end of each swinging lever 8 is engaged with a guide rod 5, an end of a presser bar spring 16 latched to the swinging lever 8 is engaged with the guide rod 5, and by the pressure of the presser bar spring 16, the moving table 4 is prevented from unexpectedly floating up from the cassette placement position B through the guide rod 5 (see the virtual line in FIG. 13).
In FIG. 11, reference numeral 17 represents movable tape guide posts for drawing magnetic tape t out of a tape cassette T and winding the tape t around a head cylinder 18, reference numeral 19 represents a full-width erase head, reference numeral 20 represents a sound erase head, reference numeral 21 represents a sound and control head, reference numeral 22 represents fixed tape guide posts, reference numeral 23 represents a back tension post, reference numeral 24 represents a capstan, and reference numeral 25 represents a pinch roller.
In the above-described structure, when the tape cassette T is injected into a tape cassette injection slot 1a of the housing 1 with the moving table 4 being on standby in the cassette injection position A as shown by the solid line in FIG. 13, since the clutch of the gear mechanism 14 is deactivated, the moving table 4 is slightly pushed in the backward direction b by the tape cassette T being injected onto the moving table 4, the clutch of the gear mechanism 14 is activated by the drive source through the worm gear 11, the worm gear 10 and the rotating cam 9 based on a detection signal from a detector (not shown) detecting that the moving table 4 is pushed, and the rotating cam 9 and the swinging levers 8 are integrally coupled so as to interlock with each other through the gear mechanism 14. Thereafter, the swinging levers 8 are rotated in the backward direction d by the drive source, so that the moving table 4 is horizontally moved in the backward direction b along the guide holes 6 and is then vertically moved down to be set in the cassette placement position B (see the virtual line in FIG. 13). Then, the magnetic tape t is drawn out of the tape cassette T (see the virtual line in FIG. 11), and an operation such as reproduction is performed.
By pressing an eject button (not shown), the swinging levers 8 are rotated in the forward direction c by the drive source through the gear mechanism 14 and the like based on the eject signal, so that the moving table 4 in the cassette placement position B is vertically moved up along the guide holes 6 and is then horizontally moved in the forward direction a to the cassette injection position A. Then, the tape cassette T is ejected (see the solid line in FIG. 13).
Showing the condition of coupling between the swinging levers 8 and the pivotal attachment shaft 7, as shown in FIG. 14, by forming a pair of upper and lower concave step portions 33 at each end of the pivotal attachment shaft 7 by cutting, protrusions 7a the cross sections of which have a substantially flat rectangular shape are formed between the concave step portions 33, and engagement holes 8b having a flat rectangular shape and formed at the base ends of the swinging levers 8 so as to pass therethrough are engaged with the protrusions 7a. 
[Problems to be Solved]
In the above-described structure, since the distance h from the position of coupling between the pivotal attachment shaft 7 and the swinging levers 8 to the guide rods 5 engaging with the concave grooves 8a is long, when a gap is formed between the protrusions 7a and the engagement holes 8b engaged with each other, the engagement backlash due to the gap is transmitted to the guide rods 5 being enlarged by a relational expression h/g (here, g is the width of the engagement holes 8b), so that the swinging levers 8 cannot be rotated in the forward and backward directions c and d in synchronicity with each other. Consequently, while moving in the forward and backward directions a and b, the moving table 4 exhibits a behavior such as inclining to come into contact with the guide plates 3a and 3b, so that it is difficult to move the moving table 4 in the forward and backward directions a and b as predetermined. As a result, the tape cassette T cannot be smoothly injected or ejected.
Moreover, since the swinging levers 8 are disposed outside the guide plates 3a and 3b, when the swinging levers 8 are coupled to the pivotal attachment shaft 7, it is necessary to insert the pivotal attachment shaft 7 into the through holes of the guide plates 3a and 3b (see FIG. 12) and then reliably engage the engagement holes 8b of the swinging levers 8 with the protrusions 7a of the pivotal attachment shaft 7 so that there is no backlash. This is cumbersome and requires time.
Further, since it is necessary to precisely cut the ends of the pivotal attachment shaft 7 to form the protrusions 7a, the cost of production is high.
In view of the above-mentioned problem, an object of the present utility model is to provide a magnetic tape apparatus into and from which a tape cassette can be smoothly injected and ejected.
[Means for Solving the Problems]
To solve the above-mentioned object, according to the utility model as set forth in Aspect 1, in a magnetic tape apparatus in which a tape cassette moving table is disposed between guide plates on a chassis so as to be movable in forward and backward directions, a pair of right and left swinging levers pivotally attached to the guide plates are engaged with guide rods provided on the moving plate, and by rotating the swinging levers in forward and backward directions, the moving table is moved through the guide rods in the forward and the backward directions between a cassette injection position and a cassette placement position set between the guide plates; the swinging levers are disposed inside the guide plates, pivotal attachment shafts provided on outside surfaces of the swinging levers are inserted in pivotal attachment holes formed through the guide plates, a coupling shaft is disposed between the swinging levers so as to be concentric with the pivotal attachment shafts and the ends of the coupling shaft bent substantially in an L shape are engaged with concave portions formed on inside surfaces of the swinging levers to thereby integrally couple the swinging levers through the coupling shaft, and disengagement preventing parts engaging with the ends of the coupling shaft engaged with the concave portions are integrally formed on the swinging levers.
According to this structure, since the ends of the coupling shaft bent substantially in an L shape are deeply engaged with the concave portions of the swinging levers substantially in an L shape, an engagement backlash is not readily caused between the substantially L-shaped ends and the concave portions, and even if an engagement backlash is caused, since the distance from the substantially L-shaped ends to the guide rods engaging with the swinging levers is short, the engagement backlash is not significantly enlarged. Consequently, the swinging levers can be reliably rotated in the forward and backward directions in synchronicity with each other through the coupling shaft, so that the moving table can be moved in the forward and backward directions as predetermined. As a result, the tape cassette can be smoothly injected and ejected.
In producing the coupling shaft, since it is necessary only to bend both ends of a bar substantially into an L shape and it is unnecessary to precisely cut the ends like the conventional method (see FIG. 14), the cost of production is low.
When the coupling shaft is coupled to the swinging levers, since it is necessary only that the pivotal attachment shafts provided on the outside surfaces of the swinging levers be inserted into the pivotal attachment holes formed through the guide plates and then, the substantially L-shaped ends of the coupling shaft be engaged with the concave portions of the swinging levers, the coupling can be performed quickly and easily.
What is important here is that the swinging levers are disposed not outside the guide plates like in the conventional apparatus (see FIG. 12) but inside the guide plates (see FIG. 2). With this, the swinging levers can be precisely placed in position by use of the guide plates, and the ends of the coupling shaft can be easily engaged with the concave portions of the swinging levers. When the ends are engaged with the concave portions, the guide plates are never obstructions, so that the coupling can be performed quickly and easily.
Further, only by engaging the ends of the coupling shaft with the concave portions of the swinging levers, the ends can be prevented from disengaging from the concave portions by the disengagement preventing parts, so that the coupling can be performed quickly and reliably.
According to the utility model as set forth in Aspect 2, in the utility model as set forth in Aspect 1, the guide plates are formed integrally with the chassis by bending a steel plate substantially into a U shape.
According to this structure, only by bending a steel plate substantially into a U shape, can the chassis and the guide plates be integrally and inexpensively mass-produced, so that low cost of production is realized.
According to the utility model as set forth in Aspect 3, in a magnetic tape apparatus in which a tape cassette moving table is disposed between guide plates on a chassis so as to be movable in forward and backward directions, a pair of right and left swinging levers pivotally attached to the guide plates through pivotal attachment shafts are engaged with guide rods provided on the moving plate, and by rotating the swinging levers in forward and backward directions, the moving table is moved through the guide rods in the forward and the backward directions between a cassette injection position and a cassette placement position set between the guide plates; a coupling shaft is disposed between the swinging levers so as to be concentric with the pivotal attachment shafts and the ends of the coupling shaft are engaged with concave portions formed on inside surfaces of the swinging levers to thereby integrally couple the swinging levers through the coupling shaft.
According to this structure, only by engaging the ends of the coupling shaft with the concave portions of the swinging levers with the swinging levers pivotally attached to the guide plates through the pivotal attachment shafts, the swinging levers can be easily and quickly coupled through the coupling shaft.
According to the utility model as set forth in Aspect 4, in the utility model as set forth in Aspect 3, the ends of the coupling shaft are bent substantially in an L shape and the substantially L-shaped ends are engaged with the concave portions of the swinging levers.
According to this structure, since the ends of the coupling shaft bent substantially in an L shape are deeply engaged with the concave portions of the swinging levers substantially in an L shape, an engagement backlash is not readily caused between the substantially L-shaped ends and the concave portions, and even if an engagement backlash is caused, since the distance from the substantially L-shaped ends to the guide rods engaging with the swinging levers is short, the engagement backlash is not significantly enlarged. Consequently, the swinging levers can be reliably rotated in the forward and backward directions in synchronicity with each other through the coupling shaft, so that the tape cassette can be smoothly injected and ejected.
According to the utility model as set forth in Aspect 5, in the utility model as set forth in Aspect 4, disengagement preventing parts engaging with the ends of the coupling shaft engaged with the concave portions are integrally formed on the swinging levers.
According to this structure, since the disengagement preventing parts are engaged with the ends of the coupling shaft engaged with the concave portions of the swinging levers, there is no possibility that the ends of the coupling shaft are unexpectedly disengaged from the concave portions, so that the swinging levers can be reliably coupled through the coupling shaft.